The proposed work combines mutant and biochemical analysis to localize the genes for ribosomal proteins in the eucaryote Drosophila melanogaster. The evolution of ribosomal proteins within the genus Drosophila will be investigated by 1 and 2 dimensional polyacrylamide gel electrophoresis. Tryptic peptide analysis, on one or two of the invariant ribosomal proteins from three species will be carried out to measure the sensitivity of our electrophoretic system in detecting mobility variation. Studies on the coordinate regulation of ribosomal RNA and protein synthesis will be carried out using drugs (5-Fluorouridine and alpha-amanatin) which differentially affect either the synthesis or maturation of ribosomal RNA or protein. These studies will be carried out in embryonic Drosophila tissue culture cells. An experiment is described which utilizes the specificity of alpha-amanatin in inhibiting the mRNA like polymerase, and autoradiography of 3H-uridine labelled chromosomes, to localize the map position of transfer-RNA genes. Studies concerned with elucidating the effects of ecdysone or macromolecular synthesis in Drosophila cell cultures are outlined. BIBLIOGRAPHIC REFERENCE: Weber, L. and E. Berger, Base sequence complexity of the stable RNA species of Drosophila melanogaster. Biochemistry 15: 5511-5519, 1976.